24 Jul
2001
24 Jul
'01
10:12 a.m.
Sellam Ismail said:
On Tue, 24 Jul 2001, Carlini, Antonio wrote:
And a test I use - a carbon-arc-lamp nicknamed "buttercup". (If there
are any ex-Dabney-House readers here, they'll get the reference.) I can
only run it intermittently, but all cyanine-based CD-R's become unreadable
after a few hours of 10% exposure to it. (I think a few hours is somewhere
around a decade of solar UV exposure.)
The CompUSA-super-duper cheapies (CMC Magnetics by the ATIP code) become
unreadable after just a few minutes. I think these use the cyanine dye
without any stabilizers at all.
I've melted pthalocyanine-based CD-R's (Kodak Ultima and Mitsui Gold) by
putting them too close to the arc, but never damaged the data otherwise :-)
Of course, two seconds in the microwave on "high" completely destroys them
*all*!
Tim.
Personally, I have only had one read-failure in
several hundred burns.
That's not counting a few coasters along the way - this was a partial
read-failure some six months to a year later when I came to use the
CD.
Wait ten or twenty years, and then make your assessment. That's what Tim
is concerned with. 
24 Jul
24 Jul
10:34 a.m.
On Tue, 24 Jul 2001 CLASSICCMP(a)trailing-edge.com wrote:
Of course, two seconds in the microwave on
"high" completely destroys
them *all*!
Some people have crumbs in their microwave ovens (I do). Tim apparently
has melted plastic and resin compounds in his, with probably smoke
streaks.
I'd hate to cook a meal in your kitchen :)
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
12:53 p.m.
Speaking of microwaves...
My roommate and I at Caltech used our microwave last year for all kinds of
fun... EPROMs, with the little window in the top, make a very impressive
orange glow. Dead lightbulbs can make greens, reds, and purples (don't
leave them in too long or they'll break, though). The best, however, is a
couple of sticks of 0.5mm pencil lead; that makes a bright orange/red glow
and the occasional ball of plasma. :-) By the end of the year the glass
cooking dish was shattered into a dozen pieces by the intense
heating/cooling cycles, and there were scorch marks everywhere, but it
still cooked just fine. Fortunately for the new tenants, the microwave was
getting replaced anyway, so we took it with us.
The rest of the apartment took quite a beating as well. :-)
ObClassicCmp: That apartment also saw a lot of dumpster-flux: junked
computers and electronics dragged home, scavenged, and the scraps going
back to the dumpster. Thus began my collection with a couple of
SparcStations and some rackmount chassis.
-Rob
On Tue, 24 Jul 2001, Sellam Ismail wrote:
On Tue, 24 Jul 2001 CLASSICCMP(a)trailing-edge.com
wrote:
Of course, two seconds in the microwave on
"high" completely destroys
them *all*!
Some people have crumbs in their microwave ovens (I do). Tim apparently
has melted plastic and resin compounds in his, with probably smoke
streaks.
I'd hate to cook a meal in your kitchen :)
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
8:25 p.m.
New subject: [OT] Re: Kodak Gold CD-R's going bye-bye?
Sellam Ismail wrote:
On Tue, 24 Jul 2001 CLASSICCMP(a)trailing-edge.com
wrote:
Reminds me of a former colleauge who was potting some electronic module
in
Epoxy. The instructions stated to cure in an oven for some number of
hours.
He figured that a few minutes in the microwave ought to to the trick so
off he went to the kitchen. (No no-one asked him whether the microwaves
might
affect the electronic vcomponents!)
The interaction of epoxy and microwaves must be quite interesting.
Apparently
there was a loud bang and the inside of the microwave was covered in a
thin layer
of perfectly cured black epoxy. Time to go off to the store for an new
microwave before the wife finds out!
-- HBP
Of course, two seconds in the microwave on
"high" completely destroys
them *all*!
Some people have crumbs in their microwave ovens (I do). Tim apparently
has melted plastic and resin compounds in his, with probably smoke
streaks.
I'd hate to cook a meal in your kitchen :)
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
25 Jul
25 Jul
9:02 a.m.
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24 Jul
24 Jul
10:46 a.m.
At 06:12 PM 7/24/01 -0400, CLASSICCMP(a)trailing-edge.com wrote:
And a test I use - a carbon-arc-lamp nicknamed
"buttercup". (If there
are any ex-Dabney-House readers here, they'll get the reference.) I can
only run it intermittently, but all cyanine-based CD-R's become unreadable
after a few hours of 10% exposure to it. (I think a few hours is somewhere
around a decade of solar UV exposure.)
I admire your thoroughness, but I think putting my media in
a cool, dark place will reduce its exposure to UV and temperature
extremes. Perhaps I'll need to worry about degeneration of
the chemicals inside the CD, or something else we're not guessing
about today. Meanwhile, I'll cross my fingers and assume I'll have
other media choices in the next 5-10 years that'll encourage me
to re-copy my CD-Rs, which have patiently waited in their
fire-proof case.
- John
11:31 a.m.
I admire your thoroughness, but I think putting my
media in
a cool, dark place will reduce its exposure to UV and temperature
extremes. Perhaps I'll need to worry about degeneration of
the chemicals inside the CD, or something else we're not guessing
about today. Meanwhile, I'll cross my fingers and assume I'll have
other media choices in the next 5-10 years that'll encourage me
to re-copy my CD-Rs, which have patiently waited in their
fire-proof case.
With the CompUSA cheapies, my original CD-R (a Philips
CDD2000) wouldn't even touch them. It definatley prefers the ones
with the dark blue dye. I've also had trouble with CD-R's being read
on older CD-ROMs on the cheapie disks while burning them on better
quality disks worked fine. Now I use a Philips Omniwriter and it's
less picky about the media and I'm still searching for consistent
good quality. I found an interesting site the other day that deals
with some of these questions though and even breaks down which
factories make which brands:
http://www.cdmediaworld.com/hardware/cdrom/cd_quality.shtml
For the moment though, on systems that are capable of using
the drive, I've been writing system backups and such to MO disks,
which are supposed to be much sturdier than CD-R's. At 230MB (3.5"
Fujitsu IDE drive) and 1.3gig (5.25" Pinnacle SCSI drive), the
capacity isn't too bad. Even my laptop has one of the Fujitsu drives
as a hot swappable expansion bay.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757
12:58 p.m.
Jeff Hellige wrote:
I admire your
thoroughness, but I think putting my media in
a cool, dark place will reduce its exposure to UV and temperature
extremes. Perhaps I'll need to worry about degeneration of
the chemicals inside the CD, or something else we're not guessing
about today. Meanwhile, I'll cross my fingers and assume I'll have
other media choices in the next 5-10 years that'll encourage me
to re-copy my CD-Rs, which have patiently waited in their
fire-proof case.
With the CompUSA cheapies, my original CD-R (a Philips
CDD2000) wouldn't even touch them. It definatley prefers the ones
with the dark blue dye. I've also had trouble with CD-R's being read
on older CD-ROMs on the cheapie disks while burning them on better
quality disks worked fine. Now I use a Philips Omniwriter and it's
less picky about the media and I'm still searching for consistent
good quality. I found an interesting site the other day that deals
with some of these questions though and even breaks down which
factories make which brands:
http://www.cdmediaworld.com/hardware/cdrom/cd_quality.shtml For the moment though, on systems that are capable of
using
the drive, I've been writing system backups and such to MO disks,
which are supposed to be much sturdier than CD-R's. At 230MB (3.5"
Fujitsu IDE drive) and 1.3gig (5.25" Pinnacle SCSI drive), the
capacity isn't too bad. Even my laptop has one of the Fujitsu drives
as a hot swappable expansion bay.
I have acquired a Sony SMO S501 and some cartridges. I understand
that the company I bought them from used them for backup for at least
5 years. While each side of the cartridge holds only 300 MBytes, at least
the total capacity (both sides) is almost equal to a CD. And although
they are a bit slow on the WRITE operation, the READ operations are
almost as fast as a hard disk drive.
I don't know about retention, but I expect I will be making a backup of the
long term files about every one or two years. Does anyone know how I
might test a magneto optical cartridge for long term degradation? Also,
if I can read the cartridge, does that indicate it is as good as when it
was written or should it always be written again after 5 years just to be
sure?
If anyone ever sees a Sony SMO S501 for $ US 20 or less, please send it
to me and I will always appreciate and accept it and pay you for the drive
and shipping in the US and Canada. Shipping from Europe is still too expensive.
Sincerely yours,
Jerome Fine
25 Jul
25 Jul
3:21 a.m.
Jerome Fine said:
I don't know about retention, but I expect I will be making a backup of the
long term files about every one or two years. Does anyone know how I
might test a magneto optical cartridge for long term degradation? Also,
if I can read the cartridge, does that indicate it is as good as when it
was written or should it always be written again after 5 years just to be
sure?
Well, I don't know for sure, but I expect they're pretty good. I know of a
local company that has ~1TB of records dating back many years on MO media, and
they use them regularly (as I understand it, anyway; I don't actually work
there) so the data's probably pretty stable...
- Dan Wright
(dtwright(a)uiuc.edu)
(http://www.uiuc.edu/~dtwright)
-] ------------------------------ [-] -------------------------------- [-
``Weave a circle round him thrice, / And close your eyes with holy dread,
For he on honeydew hath fed, / and drunk the milk of Paradise.''
Samuel Taylor Coleridge, Kubla Khan
6:16 a.m.
Dan Wright wrote:
Jerome Fine said:
Jerome Fine replies:
I guess the key question is:
"How does a user evaluate the longevity of any particular media?"
It seems unlikely that the microwave is a good fit for testing magneto optical
media. On the other hand, I would like to have some sort of idea as to how
long I can expect any files to still be readable? Also, how long is it likely
that the magneto optical drive will last. I suspect that the drives are likely
to fail before the media and it may even be more likely that I will not be able
to find a system that is able to use both the old drives and the newest drives
when it comes time to switching to a newer type. So the next question is:
"What sort of strategy is recommended to always be sure that old files (stored
on old media which can only be read with old drives) be rescued/copied to newer
media before that is no longer possible?"
Obviously, every user would like to skip as many in-between steps as possible.
But since safety is perhaps more important, where should the compromise be made?
Another question is:
"What standard needs to be used to determine what files may be of interest in
50 years, 500 years or even 5000 years?"
And realize that is probably THREE SEPARATE questions!!
It is fine to be discussing the technical details of how to save files, but if everything
needs to be saved, that creates many difficulties. For example, if some software
is being developed, it's rare that non-distribution files ever see the light of day,
much
less that they get saved beyond the next distribution. In most cases, only the final
source and executable files get saved and it is probably rare for OBJ and MAP files
to be saved. What is the best way to develop criteria that can determine which
files will be of interest to someone looking to understand how "programs" were
written 5000 years ago? Better still would be to attempt to determine the questions
that will be asked 5000 years from now. Looking back, I would suggest that the
first footstep on the Moon back in 1969 may not have been as important as the
technology that was needed to make it all possible.
I realize that this seems Off Topic, but I think it is already past due that we think
about not only which hardware needs to be preserved, but also all the software.
So much that is more than 20 years old has already been lost. But if a start is
made right now to preserve both hardware and software, then for software the
questions are very different than for hardware!
Sincerely yours,
Jerome Fine
I don't know about retention, but I expect I
will be making a backup of the
long term files about every one or two years. Does anyone know how I
might test a magneto optical cartridge for long term degradation? Also,
if I can read the cartridge, does that indicate it is as good as when it
was written or should it always be written again after 5 years just to be
sure?
Well, I don't know for sure, but I expect they're pretty good. I
know of a
local company that has ~1TB of records dating back many years on MO media, and
they use them regularly (as I understand it, anyway; I don't actually work
there) so the data's probably pretty stable...
8551
days inactive
8552
days old
9 comments
9 participants
participants (9)
-
ard＠p850ug1.demon.co.uk -
CLASSICCMP＠trailing-edge.com -
dtwright＠uiuc.edu -
foo＠siconic.com -
hansp＠aconit.org -
jfoust＠threedee.com -
jhellige＠earthlink.net -
jhfine＠idirect.com -
rnlion＠its.caltech.edu